remove Object.fromEntries polyfill for node 10 in test utils (#30657)

Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>

Author: stefanprobst

test/lib/next-test-utils.js

@@ -20,12 +20,6 @@ import treeKill from 'tree-kill'
 export const nextServer = server
 export const pkg = _pkg
 
-// polyfill Object.fromEntries for the test/integration/relay-analytics tests
-// on node 10, this can be removed after we no longer support node 10
-if (!Object.fromEntries) {
-  Object.fromEntries = require('core-js/features/object/from-entries')
-}
-
 export function initNextServerScript(
   scriptPath,
   successRegexp,